Transmission Time Interval (TTI) which determines a scheduling mode of time-frequency resources is an essential parameter in a radio communication system, such as a Long-Term Evolution (LTE) system.
With the development of communication technology, more and more applications, such as online games, virtual reality, industrial monitoring or Internet of Vehicles, have stricter requirements on time delay in communication transmission. They always expect a shorter end-to-end time delay in communication. In radio communication systems, such as the LTE system, it is found that shortening TTI can greatly reduce an air interface delay, based on the search on factors that influence the throughput of applications of Transmission Control Protocol (TCP). A relatively short TTI benefits various radio communication service, however, it also causes some problems, for example, more system overhead.
Currently, 3GPP has confirmed to study shortened TTI (s-TTI) technology. A S-TTI generally has length of two symbols, three symbols, four symbols or seven symbols. Due to system overhead, it is hard to apply existing communication control methods to the s-TTI technology.